Development and automation of a novel NET-PET tracer: [11C]Me@APPI.

Abstract

INTRODUCTION:

The norepinephrine transporter (NET) is an important target for research in neurology and psychology and is involved in the pathophysiology of many neurodegenerative diseases such as Alzheimer's disease and attention deficient hyperactivity disorder. For visualization of NET abundance and deregulation, a novel PET tracer--[(11)C]Me@APPI--has been developed.

METHODS:

For precursor synthesis, a 4-step synthesis starting from N-phenyl-o-phenylenediamine was set up. Radiosynthesis was established and optimized using standard methods and subsequently automated in a GE TRACERlabFx C Pro synthesizer. Preclinical testing was performed comprising affinity and selectivity testing on human membranes as well as stability and blood-brain-barrier-penetration using in-vitro models.

RESULTS:

Precursor molecule (APPI:0) and reference compound (Me@APPI) were synthesized with 26.5% and 21.4% overall yield, respectively. So far, 1.25±0.72 GBq [(11)C]Me@APPI with 54.35±7.80 GBq/μmol specific activity were produced (n=11). Affinity of reference compounds was determined as 8.08±1.75 nM for Me@APPI and 19.31±2.91 nM for APPI:0, respectively (n≥9). IAM-chromatography experiments (n=3) revealed a P(m) value of 1.51±0.34 for Me@APPI. Stability testing using human liver microsomes revealed that 99.5% of the tracer was found to be still intact after 60 minutes (n=4).

CONCLUSION:

Present data indicate that [(11)C]Me@APPI has promising properties to become a clinically useful NET-PET-tracer. Further in-vitro and in-vivo evaluations are currently under way.

• Authors: Christina Mark, Birgit Bornatowicz, Markus Mitterhauser, Matthias Hendl, Lukas Nics, Daniela Haeusler, Rupert Lanzenberger, Michael L Berger, Helmut Spreitzer, Wolfgang Wadsak
• Journal: Nuclear medicine and biology (Nucl Med Biol) Vol. 40 Issue 2 Pg. 295-303 (Feb 2013) ISSN: 1872-9614 [Electronic] United States
• PMID: 23265665 (Publication Type: Journal Article)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• 1-(3-(methylamino)-1-phenylpropyl)-3-phenyl-1H-benzo(d)imidazol-2(3H)-one
• Benzimidazoles
• Carbon Radioisotopes
• Norepinephrine Plasma Membrane Transport Proteins
• benzimidazole

Topics

• Automation
• Benzimidazoles (chemistry, metabolism)
• Blood-Brain Barrier (metabolism)
• Carbon Radioisotopes
• Drug Stability
• Humans
• Isotope Labeling
• Norepinephrine Plasma Membrane Transport Proteins (metabolism)
• Positron-Emission Tomography (methods)
• Quality Control
• Radiochemistry